1. Field of the Invention
The present invention relates generally to a method and apparatus for pulling and chopping plant stalks, and more particularly, to a method and apparatus for pulling plant stalks and the root system thereof, such as cotton, substantially clear of the ground and then chopping the same.
2. Description of the Related Art
The plant root system and stalk stump portion that remain in the field after various crops have been harvested, and the upper part of the stalks have been cut, may amount to more than fifty percent of the total weight or volume of the plant that was left in the field after the crops were harvested. Plant parasites feed, hibernate and use the root systems as pathways to move down and up as moisture and temperature varies. They will, therefore, survive until another crop is planted in the same or adjacent soil and migrate to the new vegetation. The same applies to crop disease.
In order to reduce or prevent further parasite breeding and hibernation, agronomists and farmers are well aware of the need to expose plant roots to the elements as soon as possible after a crop is harvested. In some areas of this country, plant roots of certain crops must be dug or plowed up by specific dates in order to reduce parasite and disease hibernation, and to qualify for government incentive payments. Although it would be impractical to manually pull any significant amount of the stalks and roots from harvested crops, no efficient mechanical stalk puller has heretofore been available. Therefore, the best farmers could do was to plow up the remaining stalk stumps and root systems with various types of plows or other ground engaging equipment. When plant roots are plowed, however, they may still be buried deeply in the ground and the farmer must still use pesticides and other chemicals to obtain adequate pest and disease control.
Various methods have been used in an attempt to mechanically pull harvested plants from the soil without having to first loosen the soil around the plant root system with some type of ground engaging tool or to dig up a large amount of soil with the roots as with a plow or disk blade, such as shown in U.S. Pat. No. 3,437,152 to Barrentine. None have been entirely successful or widely accepted though, since an implement that might work fairly well on one particular crop or soil condition may not work well at all on other crops or soil conditions.
For example, corn or similar plants with little or no tap root and that have stalks with a soft core are easily pulled from the ground and chopped. Cotton plants, on the other hand, have deep tap roots with both the stalk section extending seven to eight inches above the ground and the root system below the ground level being very dense and tough. The cotton stalk section usually contains as much as sixty percent of the total weight of the plant after the cotton is harvested and deteriorates very little if left standing in the field until spring tillage begins. These stalk sections hinder cultivation, and thus, grass, weeds and other parasite vegetation must be controlled with chemicals. When the following crop to be planted is peanuts or another crop that must be dug from the ground, these stalk sections also cause major problems in harvesting and cleaning.
To further complicate the problem, the population of cotton plants is much higher than that of many other crops and the seed are more difficult to space evenly. Also, since the cotton stalk size varies greatly, the spacing between the plants and other factors will affect the pulling of the stalks from the ground. The force required to pull a single stalk from the ground with roots attached also varies from a few pounds in moist sandy soil to more than a hundred pounds in dry stiff soil. It is not unusual for both of these conditions to exist in a field or even a single row. In order to successfully reduce or prevent parasite and disease hibernation, those stalks that require force within the higher range must be pulled in a manner to prevent the root system from breaking away from the upper stalk as it is pulled from the ground.
Once the cotton or other plant stalk and root system is pulled from the ground, it is also desirable to chop, grind or crush the vegetable matter in order to further condition the stalks for decomposition so that they can be returned to the soil as humus without causing the above-mentioned problems or promoting parasite and disease hibernation.
Depending on soil type, moisture and many other factors, dirt attached to the root systems of each pulled-up cotton stalk varies from a few grams to several pounds. The amount of soil left attached to the roots after being pulled can be reduced by increasing the rate of ground travel. It is impossible, however, to remove enough soil from the root sections to make grinding with conventional equipment feasible. Chopping or grinding and plant root exposure to the elements is enhanced by removing as much dirt as practical.
Rotary and flail type cutters are used extensively to cut the non-abrasive top sections of a wide variety of plants. The cutting edges on these machines operate at high speed to sever grass, weeds, forage crops or other plants by impact at the desired height above soil surfaces. Should these cutting edges be allowed to touch the soil, they will become dull very quickly. When the cutting edges become dull, they will no longer sever plants on impact, performance deteriorates and power consumption soars beyond acceptable levels. Soil attached to plant roots after they are pulled from the ground is very abrasive and will wear cutting edges very rapidly. When an attempt is made to grind pulled-up cotton stalks with roots attached, cutting edges on the high speed blades become dull within minutes, all cutting ceases, and the cutting or grinding machine becomes plugged and inoperative.
Cutters such as that shown in U.S. Pat. No. 4,350,207 to Ben-Dor are examples of the above described conventional machinery which have been used for many years. It should be realized, however, that prior art choppers were used for cutting primarily only the upper stalk sections. Even though these choppers did not handle the heavy roots remaining in the ground, many problems were still associated with these type of choppers, especially when used for cutting cotton and similar plant stalks. They were, however, simple choppers and the power requirement was relatively small, which allowed them to be pulled by draft animals without the need for external power transmission drives. Since these choppers replaced vast amounts of manual labor, the requirement for disconnecting, cleaning, sharpening and servicing them frequently was not considered a major factor in years past. Conditions and machinery are quite different today, however, since machines operate at as much as ten times the ground speed and cover eight or more times as many rows, thus presenting today's machinery with new factors to be considered and problems to be solved. For example, although cotton stalk limbs normally have a soft pith core and are comparatively brittle when dry, the root and lower main stem are as tough as maple or similar hardwood saplings of comparable size, which further aggravates the use of prior art choppers with modern machinery. When tough material such as the part of the cotton stalks above ground level is cut by rolling choppers, the cut sections tend to wedge between the chopper blades. Blades on prior art rolling chopper cylinders were, therefore, normally mounted at two or more points in a manner to leave a center area between blades open so that part of the chopped material could pass through and reduce wedging between adjacent blades. This worked well on corn and other soft or fragile stalks when the roots remained in the ground and the volume of chopped material is not too great. When ground engaging rolling choppers of this type were used to cut cotton stalks, however, material accumulated within the center cavity of the rotor and had to be extracted manually. This is a very difficult and time consuming task. Operators of modern tractors or machines, many of whom have more power under their control than hundreds of draft animals would ever produce, will generally not leave a comfortable seat in a climate controlled cab and clear a plugged rolling cutter more than once or twice before the machine would be declared inappropriate for the job. Further, for the reasons discussed above, it is also desired to chop the complete plant stalks with the roots attached, a task which is much more difficult and must address many other factors not confronted by the rolling choppers of the prior art.
Additional concerns related to pulling and grinding plant stalks, which have not been adequately solved by the prior art, include the soil attached to the root systems of pulled stalks causing the cutting edges of high speed blades to wear away very quickly; flying stalk particles, when propelled at high speed by the cutter blades, puncturing the pneumatic tires when a high speed cutter is operated in association with the puller; complexities in conveying and feeding the pulled stalks into an attached cutter or hammer-mill; and difficulty in mechanically lifting the stalks, the heavy center section of which lies in a straight line and conveying them into a grinding or cutting device after they are discharged to the ground from the puller.
A further concern with prior art stalk pullers and choppers is being able to transport the machine from one field to another over public roads. Implements such as plows, row bedders, planters, and cultivators are mounted on standardized tractor three point hitch systems. These systems allow operators to have precise control over implement position, operating depth and row alignment. Tractor mounted implements are lifted and carried by the tractor at the end of one row, and then transported to another field. Wide mowers, disk harrow and many other farm implements do not need to be closely aligned with a row pattern. These machines extend too far behind the tractor to be lifted so they are usually mounted on wheels and trail behind the tractor. The end sections of these machines must, however, be folded when transported over public roads because of their great width. Several prior art systems have been used for retracting or folding the end sections of such wide implements. Planters or similar light weight implements with seed or similar hoppers employ long positioning arms to stack end units above those mounted on a center tool bar. This system cannot be used in applications where the machine components are comparatively heavy or subject to sever stress. Thus, the end sections of heavy implements, having no hoppers filled with seed or other materials, are usually upended vertically to reduce the width for transport since rotating a heavy load more than ninety degrees with a single hydraulic cylinder is seldom feasible.
Accordingly, there is a great need for an apparatus to pull and grind plant stalks after harvesting, in particular, cotton stalks and other plants having deep root systems. There is a need for the apparatus to operate efficiently day after day under most conditions without plugging and without the operator having to leave his seat to service or adjust the machine, and for the apparatus to be transportable across public roads.